1. Field of the Invention
The present invention relates to special-purpose hardware or a method for performing data merging/sorting and searching in a database or file processing, and more particularly to a method and apparatus for merging/sorting and searching which are flexible with respect to change of data length.
2. Description of the Prior Art
As database-oriented hardware for merging/sorting and searching, there is, e.g., a heap sort type engine proposed by the inventors (Tanaka, Y. et al: Pipeline Searching and Sorting Modules as Components of a Data Flow Database Computer, IFIP Congress 80, pp. 427-432, Oct. 1980). This engine can completely overlap the transmission and sorting calculation of data, and can therefore perform a very efficient computation. This engine, however, has been problematic in the following points:
(1) Due to complicated circuitry, the number of elements is too large and poses a problem in the LSI implementation.
(2) There is no expansibility for the alteration of a data length.
Another sorting engine is, e.g., a merge sort type engine (Todd, S.: Algorithm and Hardware for a Merge Sort Using Multiple Processors, IBM J, R&D, vol. 22, no. 5, May 1978). Since the merge sort is simpler in the calculative system than the heap sort etc., it can simplify hardware, but it has not solved the problem (2).